What are the problems?
Paints consist of a colouring agent or pigment (something that will bind the colourant to the surface) and solvents, (which keep the paint liquid until applied). Synthetic paints are made mainly from petrochemical-based ingredients, by-products of the environmentally damaging oil industry. Paint manufacturing creates lots of toxic waste - typically 10 litres of waste for each litre of paint, but the ratio can be as much as 30 to 1 for specialist paints. Modern emulsions are water-based, with vinyl or acrylic resins added to make them more hardwearing. The amount of resin determines the varying degrees of sheen seen in matt, eggshell, silk and satin finishes. Gloss paints are oil-based and include resins to give them a hardwearing quality.
The organic* solvents used are themselves toxic, but also give off VOCs (volatile organic* compounds) as the paint is being applied and after it is dry. Common VOCs in paints, primers and varnishes include benzene, formaldehyde, kerosene, ammonia, toluene, and xylene, all of which are known carcinogens & neurotoxins. Exposure to VOCs can irritate your eyes, nose, throat and skin & are proven to increase allergies, asthma, respiratory problems and central nervous system problems. Many cases of 'sick building syndrome' have been traced to chemicals in interior paints. VOCs also react with the nitrous oxides in air to form ozone. Alkyd paint (most conventional oil-based paint) will off-gas VOCs, as they are often more than 50% organic solvent. High gloss paint tends to contain more solvent, while high solids paint contains less. Acrylic paint uses water as the main solvent, but will contain a small amount (10%) of organic solvent.
* 'organic' is used here in the strictly chemical sense, meaning chemical compounds based mainly on carbon and hydrogen. Over half of all chemical compounds come under this definition, including the main constituents of the fossil fuels (oil, natural gas and coal).
In addition, paint contains fungicides and heavy metals (e.g. cadmium). Many (especially bright whites) include a lot of titanium dioxide, which is considered an occupational carcinogen and a cause of lung fibrosis by the US National Institute of Occupational Health and Safety. The disposal of synthetic paints and related products can lead to these materials being released into the wider environment, e.g. contaminating water supplies.
In 1989 the World Health Organisation's International Agency for Research on Cancer reported that professional painters are 40% more likely to contract cancer. Most of us spend about 90% of our time indoors, and the combination of chemicals emitted from the fabric and furnishings of modern buildings including paint may be implicated in Sick Building Syndrome - headaches, nausea, and general ill health of the occupants.
What should I look for?
Tins of paint now state the VOC content. Generally gloss paint for interior & exterior wood and metal has a high level of VOC and water based emulsion a low level. Acrylic paints, a water based alternative to gloss, which use water as the solvent, don't contain VOCs but have extra harmful chemicals/additives in order to make them soluble in water. High solids paint uses less solvents than other gloss paints. If you do buy standard paint, go for a water based one with a low VOC content or look for paints with an eco-label. The European Eco-label looks at VOC content and also embodied energy and titanium dioxide content. It has been awarded in several European countries outside the UK, but at present, has yet to be taken up again by UK paint manufacturers.
Safer alternatives exist. Some contain no chemical solvents, while other, more widely available commercial brands just contain a lower percentage of VOCs than conventional paints. Eco-friendly paints use plant-based resins, oils and dyes - which are renewable resources, biodegrade on disposal and require less energy to produce. For example: natural solvents such as turpentine or d-limonene as alternatives to white spirit; instead of plastic binders they may use linseed oil and casein and chalk and clay may replace fillers such as titanium dioxide; colours are often derived from natural earth and mineral pigments. Chemical paint forms a plastic 'skin' over the wood and can therefore blister if water is trapped beneath it but natural paint doesn't do this as it bonds with the timber. Future coats can also be applied without rubbing down.
There are a wide range of natural paints available, for internal and external use; for wood, concrete and metal. Also organic wood stains, varnishes and waxes. They're usually more expensive than conventional brands, but they're less harmful to the painter and to the occupants of the building. You can also get environmentally friendly paint stripper, which is water based and solvent free, and brush cleaners made from natural ingredients such as rape seed oil. Turpentine is also plant based but is still toxic if inhaled so ventilate well.
For any product, even eco ones, read the label and follow recommendations for safe use and disposal. Disposal of paints & cleaning agents into the drainage system contaminates water and is harmful to plants and animals. Many local authorities will collect unwanted paints and paint strippers from households. If yours doesn't, pester them!
If you would like a list of suppliers of natural paints & finishes, do contact us.